While diet has the greatest impact on your weight, exercise is an important part of the total equation. It’s the ultimate levering agent for optimal health too. Exercise influences your biology in so many ways, it’s virtually impossible to pin down its benefits to one particular thing.
That said, recent research suggests a fat-burning hormone, released during exercise, plays a role. This hormone, irisin (aka, FNDC5), helps your body shed fat and keeps body fat from forming in the first place. As reported by Epoch Times:
“Irisin appears to work by boosting the activity of genes and a protein that are crucial to turning white fat cells into brown cells. It also significantly increases the amount of energy used by those cells, indicating it has a role in burning fat.”
Tests show irisin is able to suppress fat cell formation by 20 to 60 percent. Normally, your body produces only small quantities of irisin. Exercise is the key to boosting its production.
Fat-Busting Hormone Also Improves Heart Function and More
Previous research into the effects of irisin — which is also classified as a myokine, meaning a cytokine or chemical messenger produced by muscle — suggests it has a number of beneficial health effects, including
- Reducing arterial plaque buildup by preventing the accumulation of inflammatory cells, hence lowering your risk of atherosclerosis
- Increasing the metabolic rate and energy expenditure in your myocardium (the thickest layer of your heart muscle)
- Increasing mitochondrial biogenesis
- Inducing telomere elongation in cells. In humans, telomere length and integrity play a role in diseases, disease susceptibility, and aging.
Short telomeres are a risk factor for many diseases, including decreased immune function, diabetes, neurodegenerative diseases, atherosclerotic lesions, and DNA damage
Irisin May Improve Diagnosis of Common Endocrine Disorder
Interestingly, irisin may also be used as a marker for polycystic ovary syndrome(PCOS) in teenage girls. As such, it may allow doctors to diagnose the condition easier and result in earlier treatment.
PCOS is the most common endocrine and metabolic disease affecting women of reproductive age (puberty to menopause). An estimated 10 to 20 percent of women of reproductive age struggle with this problem.
While many of the symptoms involve the ovaries, these abnormalities are the result of a much larger metabolic problem. Common criteria for a diagnosis of PCOS include:
- The complete or almost complete lack of ovulation
- Increased androgen (male hormone) production; facial hair and/or acne
- Hyperinsulinemia (insulin resistance with elevated serum insulin levels)
Any hormone problem that interferes with normal ovulation results in what is known as a “polycystic” ovary which, regardless of the cause, will produce increased amounts of androgen. Conversely, increased androgen production interferes with normal ovulation.
Evidence suggests obesity plays a role in the androgen excess syndrome; overweight women produce increased androgens even if they have no underlying abnormality in the adrenal gland.
The Benefits of Brown Fat
Getting back to the main focus of this article, irisin appears to be an important player in weight loss associated with exercise. As mentioned, a key part of this benefit is due to its ability to transform white fat cells into brown fat cells, the latter of which primarily burn energy rather than storing it.
Based on animal models, researchers estimate that just 50 grams of brown fat (which is less than what most study volunteers have been found to have) can burn about 20 percent of your daily caloric intake, so the impact of having more brown fat can be rather significant.
Research has shown that certain groups of people tend to have more brown fat than others, and there are direct correlations between the activation of brown fat and metabolic measures of good health. For example:
- Slender people have more brown fat than obese people do
- Younger people have more brown fat than older people
- People with normal blood sugar levels have more brown fat than those with high blood sugar
Brown Fat Is More Akin to Muscle Than Fat
As newborns, we have a healthy supply of brown fat to keep warm, but by adulthood, we lose most of our brown fat stores, which are typically found in the neck area, around blood vessels (which helps warm your blood), and “marbled” in with white fat in visceral fat tissue. The good news is you can increase your supply of brown fat. In addition to exercise, brown fat can be activated through cryotherapy, meaning exposure to cold temperatures such as ice baths or cold showers.
Interestingly, brown fat actually behaves more like muscle than fat, which helps explain its fat-burning capabilities. Bruce Spiegelman, Ph.D., has published a number of studies on brown fat, and in one, he identified a “master switch” that promotes the production of brown fat. This molecular switch, known as PRDM16, regulates whether immature cells will turn into brown fat or into muscle cells.
So white and brown fat cells have very different origins. Brown fat is more closely related to muscle. Another set of researchers from Harvard’s Joslin Diabetes Center found yet another trigger for brown fat — a bone morphogenetic protein called BMP-7, which also promotes bone growth.BMP-7 acts as a growth factor for brown fat.